Can't figure it out why sometimes car runs smooth and other days runs like a donky! Bucking about under acceleration or if take foot off accelerator for a second to allow natural slow down then put power on again it jumps about all over the place. At idle say at the lights for instance I can see the rev counter moving up and down by about +/- 5mm and feel the car shuddering ever so slightly like the engine mix is not right somehow. Anyone else had this problem? Maybe I should take it to a tuner? But I still get up to 51mpg out of car, especially since keeping tyres inflated to recommended pressure. It's just the running of the engine seems very erratic every day.

probably the pcv valve,i had the revving issue with mine until i changed it

*just noticed yours is a diesel,they dont have a pcv but they do a component that does the same job (i cant remember what its called :think: *

Edited 11 July, 201213 yr by pastie

Or coil pack, or throttle body clean. start with pcv

Thanks chaps, what about running a cleaner through it like

BG 244 will that help?

In this case I would say its more than a clean through job.

change the pcv,maybe fit an oil catch can,but its not essential

Is there a pcv on a diesel vrs?

i do believe it is called a ccv

there is a good bit of info in here,bear in mind thats a pd130 engine and yours is a cr170 so they wont be exactly the same.

http://www.briskoda.net/forums/topic/100913-diy-guide-the-elephant-hose-ccv-catch-can-mod/

I have a PD170 but guess the ccv is the same. Thanks.

Welcome to the world of the DPF (Diesel Particulate Filter).

Mine is the same, some days as smooth as silk, other days you'd think the wife was driving :think:

But I always keep the engine revs up to the 2000 mark as much as possible to ensure the light doesn't come on, I thought that would keep the DPF clean?

Mine has excaly the same problem,but without the revs going up and down.sometimes runs fine then well slow down starts to hold back ,jerkim at a loss myself s to what is causing this.

Irrespective of whether or not the DPF needs to perform a regeneration (regen) it is programmed to regen every 600-700 miles.

Even though the light doesn't come on this doesn't mean the DPF isn't performing regular regens.

The light only comes on when the soot level reaches a certain point and the conditions the DPF needs to be able to perform a regen aren't met.

Must admit I try not to stray too much below 2k when driving along. Have had a couple of hesitant acceleration incidents since buying the car and both times have been on full throttle in 3rd after coming off and accelerating away from a roundabout. Car gets to about about 3k and then it momentarily stops (like a flat spot), then takes off again and so on and so on. I don't rev it right out so don't know if it would continue like this all the way to the rev limit (what is it set at on the TDi PD anyway?). Change into 4th and it's fine. On lesser throttle it's fine all the time and the idle is always rock steady. Never had any check lights come up while it does or seen the DPF light (touch wood quickly).

I used to have this intermittently, but now it's most days, and often results in the car going into limp mode, just after the kangerooing described above. When this happens the ecu logs P0299 Turbo Underboost. Switching the car off and on again resets.

Not yet taken it to a specialist to have it fixed, but limp mode is seriously boring.

So back to the main point of this thread, it appears the problem is a result of a clogged or faulty ccv, anyone got a price for a replacement? I'll get the garage to fit it when it's in for service next week. Is there anything else of that nature it could be whilst it's got it's bonnet up that the garage could replace at the same time?  Apart from this problem it's otherwise a cracking car.

Edited 25 September, 201312 yr by Skoda convert

Just been down to my local garage who say they've never heard of a PCV or CCV!  That's a little worrying!!  Maybe I should replace it myself.

PCV valves have been fitted to cars since the early 70's. 

Anyone in in the motor trade who doesn't know what they are should not be allowed to touch your car.